A Connes-amenable, dual Banach algebra need not have a normal, virtual diagonal

Abstract

Let $G$ be a locally compact group, and let $WAP(G)$ denote the space of weakly almost periodic functions on $G$. We show that, if $G$ is a $[SIN]$-group, but not compact, then the dual Banach algebra $WAP(G{)}^{\ast }$ does not have a normal, virtual diagonal. Consequently, whenever $G$ is an amenable, non-compact $[SIN]$-group, $WAP(G{)}^{\ast }$ is an example of a Connes-amenable, dual Banach algebra without a normal,virtual diagonal.

16 pages; some more, minor revisions